Bacterial infections Flashcards
what is Impetigo?
Superficial infection of the skin caused by Streptococcus pyogens and/or Staphylococcus aureus
how is impetigo spread? during what times is it most common?
Contagious and easily spread in crowded or unsanitary living conditions
Peak occurrence during summer or early fall in hot, moist climates
Impetigo is Most common in what group?
school-aged children
Clinical presentation of Impetigo:
Superficial vesicles that quickly rupture and become covered in a thick, amber crust; pruritus common
Facial lesions often around nose and mouth
Many cases arise in areas of damaged skin
How is impetigo diagnosed?
Presumptive diagnosis based on clinical presentation
Definitive diagnosis requires isolation of causative organisms in culture of skin
what is found in the tonsils of someone with Tonsillolithiasis?
(tonsil stones)
Convoluted crypts of the tonsils are commonly filled with:
- desquamated cells
- foreign debris
- bacteria
what is the name for the mass of cells/debris found in patients with Tonsillolithiasis?
Tonsillar Concretions
what are Tonsilloliths?
when tonsillar concretions CALCIFY
does not happen in all cases of tonsillolithiasis
Clinical presentation of Tonsillolithiasis:
Enlarged crypts filled with yellowish debris; varies from soft to fully calcified
Variable size
Foul smelling
Solitary or multiple
when taking radiographs of patients with Tonsilloliths, these stones may present as radiopacities overlying the midportion of the _____________
ascending ramus
what organism causes syphilis?
Caused by the spirochete Treponema pallidum
signs of primary syphilis:
Relatively painless ulceration – “chancre”
Develops 3-90 days after exposure
Most affect genital region;
signs of secondary syphilis:
Develops 4-10 weeks after initial infection
Erythematous maculopapular cutaneous eruption
Painless generalized lymphadenopathy
Mucous patches & condylomata lata of oral mucosa
Split papules at angles of mouth
after secondary syphilis symptoms resolve, the infection may enter a _______ period
latent period
tertiary syphilis develops after how long?
Develops after a latency period of 1-30 years
what symptoms of a tertiary syphilis infection can be seen by a dentist?
Gumma formation
Oral involvement may produce palatal perforation
T/F: over half of patients with untreated secondary syphilis will develop tertiary syphilis
FALSE
only 30% progress to tertiary
what diseases are caused by congenital syphilis?
Saddle nose deformity
Saber shins
Hutchinson’s triad
what are the 3 characteristics of “Hutchinson’s triad”?
Malformed incisors (“Hutchinson’s incisors”) and molars (“mulberry molars”)
Ocular interstitial keratitis
Eighth nerve deafness
what are the 3 ways syphilis can be diagnosed?
1) Screening tests, e.g., VDRL, RPR
2) Specific antibody tests, e.g., FTA
3) Dark-field microscopy for non-oral lesions
Primary and secondary syphilis lesions show intense __________ infiltrate
plasmacytic
Tertiary (gumma) syphilis is characterized by what type of inflammation?
granulomatous inflammation
Spirochetes (like syphilis) can be identified using the ____________ stain
Warthin-Starry
Worldwide, how many people become infected with TB each year?
9 million
2 million die per year
how many people in the U.S. have a latent TB infection?
10-15 million
Clinical features of TB:
Only 5% of infected patients progress to active disease within 2 years after exposure
Low grade fever, night sweats, fatigue
Weight loss (“consumption”)
Chronic bloody cough
LYMPH NODE SWELLING
characteristics of Oral TB lesions:
Solitary chronic painless ulcer
Most common on gingiva and tongue
May be due to hematogenous or direct implantation of organisms
How is TB diagnosed?
Positive skin test with PPD (only indicates exposure)
Chest radiograph
Culture (may take 4-6 weeks)
Identification of organisms in biopsy material or sputum
Molecular testing (PCR, etc.)
what type of inflammation is characteristic of a Tuberculosis infection?
what cell type is predominant in these areas of inflammation?
Usually necrotizing granulomatous inflammation (“caseous necrosis”)
Multinucleated giant cells
what antibiotic treatments are available for TB?
*** Isoniazid (INH), rifampin, and pyrazinamide daily for 2 months
- Then, INH and rifampin (daily, 2x or 3x weekly) for 4 mos.
Ethambutol or streptomycin also used
____________ is a bacteriostatic antimycobacterial drug
Ethambutol
how long after the start of antibiotics is a patient with TB considered to be non-contagious?
2 weeks
what causes Actinomycosis?
Caused by any of several Actinomyces species that normally inhabit the mouth
besides the oral cavity, what other locations are susceptible to Actinomycosis?
Abdominal (25%), pulmonary (15%) or cervicofacial (55%) areas may be affected
(most are cervicofacial/oral in location)
_____________ Actinomycosis May follow dental extraction or untreated dental disease
Cervicofacial
clinical signs of Cervicofacial Actinomycosis:
Diffuse swelling and erythema
Draining sinus tracts
“Sulfur granules”
what composes the “sulfer granules” of Actinomycosis?
colonies of organisms in purulent exudate
describe the histopathology of an Actinomycosis infection:
- Filamentous bacteria that form colonies
- Bacterial colonies surrounded by neutrophils
- Adjacent tissue may show granulomatous inflammation or granulation tissue
what is the treatment for a patient with Actinomycosis?
Removal of offending tooth
High-dose antibiotics, usually IV PCN for 2 weeks, then oral PCN for 2 weeks
Periapical actinomycosis usually responds to less aggressive treatment
what is the clinical term for an existing skin lesion that becomes affected by impetigo?
“Impetiginized”
- prexisting dermatitis, cuts, scratches, insect bites, etc
